Perhaps it was inevitable that with the first female nominee of a major political party on the ballot, the race for president would have undercurrents of sexism. But what wasn't inevitable is just how out in the open it has been.

It is nearly impossible to separate out everything underlying this moment in history. Would this type of vitriol be directed at any woman trying to reach the highest office in the land? Or is there something unique about Clinton, who has been on the political stage disrupting norms and drawing ire from Republicans for decades. And what about her opponent? If Clinton were running against someone else, would this still be happening?

'Is this what we are teaching our little boys?'

How much responsibility does Donald Trump have to bear? For strategists aligned with the previous two Republican presidential nominees, quite a bit.

"I don't think that Jeb would have allowed that — or any of the other candidates," said Katie Packer, who was deputy campaign manager for Republican Mitt Romney in 2012.

Steve Schmidt, a senior adviser to John McCain's 2008 campaign, also blamed Trump.

"He's created a permissible environment for this," he said.

Schmidt and Packer are not Trump fans. But they speak from the experience of being part of the rigors of campaigns with GOP nominees for president that both also ran against another candidate whose very presence on the ballot challenged a historical norm — Barack Obama.

Schmidt remembers a famous moment from 2008.

"There was anger," Schmidt said, "and there was angst and, as Sen. Obama was moving towards election to the presidency, the crowds became angrier frankly at the end of the campaign."

At one point, a woman stood up at and said, "I can't trust Obama. I have read about him, and he's not, he's not, he's a-- he's an Arab."

McCain went on, "He's a decent, family man, citizen, that I just happen to have disagreements with on fundamental issues, and that's what this campaign is all about."

McCain never became beloved by the base the same way his running mate, Sarah Palin, did, and that was, in part, because of his willingness do things like that.

This time around, perhaps unsurprisingly, there's been no moment like that — though there's been plenty of opportunity.

Packer points to pictures of parents standing with their children at rallies with a variety of shirts and signs describing Clinton in crude sexual terms.

"Is this what we are teaching our little boys?" Packer asked. "Is this what we're teaching these kids is an appropriate way to treat women that you don't agree with? And there hasn't been a peep from the campaign about this stuff being offensive. And, so, by not addressing it, they have encouraged it."

Those T-shirts aren't sold by the campaign — and the lowest-common denominator has a way of thriving on the periphery of all campaigns. But Packer and Schmidt argue Trump's own words have fostered sexism rather than tamping it down.

The woman's card

For example, there was Trump accusing Clinton of playing the "woman's card."

"Well, I think the only card she has is the woman's card," Trump said in April during a victory speech after sweeping five primaries. "She's got nothing else going on. And frankly, if Hillary Clinton were a man, I don't think she'd get 5 percent of the vote. The only thing she's got going is the women's vote. And the beautiful thing is that women don't like her, OK?"

He doubled down on that, telling a crowd in Spokane, Wash., a couple weeks later: "If she didn't play the woman's card she would have no chance, I mean zero, of winning."

Clinton shrugged it off — and tried to use it to her advantage. "If fighting for women's health care and paid family leave and equal pay is playing the woman card, then deal me in," she said in a campaign video after Trump's remarks.

"Deal me in" became something of a call-and-response catchphrase for Clinton. The campaign even began selling a pink $5 "Woman Card."

'I just don't think she has a presidential look'

Trump, who has made plenty of derogatory comments about women's appearances in this campaign, said last month of Clinton, "I just don't think she has a presidential look. And you need a presidential look. You have to get the job done."

Asked directly about his comment that he didn't think Clinton "has a presidential look" during the first debate, Trump again said, "She doesn't have the look" before immediately pivoting to talking about her "stamina."

'I wasn't impressed'

Then there was the time, at a rally, where he was talking about the second debate, the town-hall style event where the candidates walked around on stage.

"She walks in front of me, you know, and when she walked in front of me, believe me, I wasn't impressed," he said to hoots and laughter from the crowd.

Clinton occasionally nods to her potential at making history, but she studiously avoids talking about the sexism directed at her. Instead she deflects, talking about sexism and chauvinism aimed at others.

Backlash with women

Packer, who has made a specialty of helping Republicans better communicate with female voters, said women do notice Trump's language and recognize it.

"The kinds of women that Trump would need to win in a general election really recoil at that," Packer said, "and it's the kind of thing that causes them to want to defend Hillary."

And that has shown up in the polls. Since the first debate, and especially since the leaked audio of Trump bragging about groping and kissing women, Clinton's lead has expanded. It's been because of those very kinds of women — white, suburban, college-educated. It's why places like Pennsylvania, Colorado and New Hampshire have moved more strongly to her corner.

In 2008, when Clinton ran in the primary, there were certainly signs of sexism. Saturday Night Live joked about a perceived double standard she seemed to face in the debates.

And, if you wanted to, you could buy a pantsuit-wearing Hillary Clinton nut cracker. (Actually, it is back for 2016 with a longer suit jacket to match Clinton's new style).

But this time — as she gets closer to that highest, hardest glass ceiling — it's even more out in the open, said Debbie Walsh, who heads the Center for American Women and Politics at Rutgers.

"It is ironic in so many ways," Walsh said, "that the person that this woman is running against kind of is almost a caricature of this uber-masculine guy with just tremendous bravado."

So maybe it was fitting that in the waning minutes of the final debate, as Clinton was answering a question about Social Security — and again getting in a dig at her opponent's taxes — Trump would interrupt.

"Such a nasty woman," he interjected.

Many female voters, especially millennials, scoff at the idea of supporting Clinton just because she's a woman, but moments like that have experts predicting 2016 could have a historically large gender gap — with women overwhelmingly supporting Clinton.

Copyright 2016 NPR. To see more, visit http://www.npr.org/.

DAVID GREENE, HOST:

Maybe it was inevitable that with the first female nominee of a major political party, there would be undercurrents of sexism in the race for president. What was not inevitable is just how out in the open it's been. NPR's Tamara Keith has been exploring the dynamic of gender and sexism in the campaign.

TAMARA KEITH, BYLINE: The men parked their white work van on a patch of dirt down the road from the college where Hillary Clinton was set to give a major speech. Then they attached a banner. It was almost as long as the van, with bold red and black vinyl lettering, Trump that Bitch. They waved and smiled as people walked by. The message wasn't subtle. It also wasn't an outlier. It's a slogan found on T-shirts at most every Trump rally.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED CROWD: (Chanting) Lock her up.

KEITH: It is nearly impossible to separate out everything underlying this moment in history. Would this type of vitriol be directed at any woman trying to reach the highest office in the land? Or is there something unique about Clinton, who's been on the political stage, disrupting norms and drawing ire from Republicans for decades? And what about her opponent? If Clinton were running against someone else, would this still be happening?

KATIE PACKER: I don't think that Jeb would have allowed that - or any of the other candidates.

KEITH: Katie Packer was deputy campaign manager for Mitt Romney in 2012. Steve Schmidt, who was a senior adviser to John McCain, also points to Trump's role.

STEVE SCHMIDT: He's created a permissible environment for this.

KEITH: Schmidt and Packer are not fans of Trump. But they also speak from the experience of being part of campaigns that ran against another candidate whose very presence on the ballot challenged a historical norm, Barack Obama. Schmidt remembers a moment from 2008.

SCHMIDT: There was anger, and there was angst. And as Senator Obama was moving towards election to the presidency, you know, the crowds became angrier, frankly, at the end of the campaign. And very famously, you know a woman stood up, and, you know, with great anger and vitriol said...

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED WOMAN: I can't trust Obama. I have read about him, and he's not - he's an Arab. He is not...

JOHN MCCAIN: No ma'am, no ma'am. He's a decent family man, citizen that I just happen to have disagreements with on fundamental issues. And that's what this campaign is all about. He's not...

KEITH: This time around, there's been no moment like that, though there's been plenty of opportunity. Packer points to pictures of parents standing with their children at rallies with a variety of shirts and signs describing Clinton in crude sexual terms.

PACKER: Is this what we're teaching our little boys? Is this what we're teaching these kids is an appropriate way to treat women that you don't agree with? And there hasn't been a peep from the campaign about this stuff being offensive. And so by not addressing it, they have encouraged it.

KEITH: Those shirts aren't sold by the campaign. And the lowest common denominator has a way of thriving on the periphery of all campaigns. But Packer and Schmidt argue with Trump's own words, he has fostered the sexism rather than tamping it down.

(SOUNDBITE OF ARCHIVED RECORDING)

DONALD TRUMP: Well, I think the only card she has is the woman's card.

She doesn't have the look. She doesn't have the stamina.

She walks in front of me, you know? And when she walked in front of me, believe me, I wasn't impressed.

KEITH: Clinton occasionally nods to her potential at making history. But she studiously avoids talking about the sexism directed at her. Packer, who's made a specialty of helping Republicans better communicate with female voters, says women do notice Trump's language, and recognize it.

PACKER: The kinds of women that Trump would need to win a general election really recoil at that. And it's the kind of thing that causes them to want to defend Hillary.

KEITH: In 2008, when Clinton ran in the primary, there were certainly signs of sexism. But this time, as she gets closer to that highest, hardest glass ceiling, it's even more out in the open, says Debbie Walsh, who heads the Center for American Women and Politics at Rutgers.

DEBBIE WALSH: It is ironic in so many ways that the person that this woman is running against is kind of almost a caricature of this uber-masculine guy with just tremendous bravado.

KEITH: So maybe it was fitting that in the waning minutes of the final debate, as Clinton was answering a question about Social Security and getting a dig in at her opponent, Trump would interrupt to say this...

(SOUNDBITE OF ARCHIVED RECORDING)

HILLARY CLINTON: What we want to do is to replenish the Social Security trust fund...

TRUMP: Such a nasty woman.

SCHMIDT: Many female voters, especially millennials, scoff at the idea of supporting Clinton just because she's a woman. But moments like that have experts predicting 2016 could have a historically large gender gap, with women overwhelmingly supporting Clinton. Tamara Keith, NPR News. Transcript provided by NPR, Copyright NPR.